I guess you just got to be street smart and be wary of the surroundings and the people around you.

there's this saying,

如果不砍老外那砍谁啊？If we don't scam the tourists, then who else is left of us to scam?

However, IME, The chinese will try to scam everyone.

For instance, suppliers will quote you prices without taxes (Fa Piaos) then when you want Fa Piaos, the tax rate for instance is 6% they want to charge you 12% and pocket the difference.